I have not been a participant in the creation of this light. I sure plan on buying one though. For whatever it’s worth, I’m with Wilson. Go with the safer option.
The FW3A implements a few things to reduce the heat issues compared to a D4…
Three emitters instead of four.
Regulated output up to ~1100 lm instead of ~150 lm.
Button on tail instead of side, so it’s harder to hit by accident.
Much faster access to lockout, and less need to exit lockout for quick tasks.
User-adjustable ramp ends, so the ceiling can be lowered.
Default ceiling is ~1100 lm instead of full turbo (though turbo is still accessible).
Smoother regulation which is less prone to overshooting and oscillating.
Temperature sensor calibration, for more consistent and predictable behavior.
Muggle mode, for use while lending the light to others.
… but it has less thermal mass and is still rather overpowered on turbo. The highest mode is like 500% of its sustainable power level, and the potential change would make it drop down faster to ~150% or ~200% where the regular algorithm works better.
I think you should err towards B as well. Whether it's the full-on "drop straight to regulated" or altering the ramp-down to be a lot more aggressive, it seems clear the "invisible" stepdown just doesn't work. It wouldn't on the D4 either. About how long will it run on turbo before stepdown?
I would prefer option B (with a fast but smooth step-down over the course of a few seconds).
I don't like lights that can become too hot to hold (and I don't want to have to worry about the light). Also if the light becomes too hot (with option A) it could potentially cause the thermal regulation to overshoot (which is of course undesirable).
BTW: have options to lower the sensor lag been discussed? For example these silicone rubber things could improve things a bit.
Coffee without coffee?
Powerful flashlight without power?
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*That’s a lot of 3000 lumen? Make it 2500 lumen.
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5 or 10 second turbo? I don’t accept it.
If that’s what it is, I don’t buy.*
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I have two, D4 Emisar, with Nichia 219CT 83CRI, 5000K and XP-L hi,
Nicha gets very hot.
XP-L hi also heats up, but less so.
Step Down works
and the leds don’t burn out.
D4 managed to have a generic algorithm. Is FW3A hardware harder to regulate?
On which side of the driver is the MCU? Does if face battery of shelf?
Maybe it would be possible to shorten the thermal path by installing a silicone cube or adding a blob of thermal glue in the factory?
There’s really not room for a thermal cube. A blob of thermal glue between the MCPCB shelf and MCU might work, but then it makes the light significantly less mod-friendly.
The D4’s regulation algorithm worked, but its initial peak was too hot and it had a tendency to overshoot, oscillate, and jump around. It has a reputation as a firestarter or a “nut roaster”. The FW3A improves on those things, but the initial peak is still too hot. So I’m pondering whether to make it initially act more like a turbo step-down before handing control back to the usual regulation algorithm.
In either case, the user can still force it to stay at turbo by setting the ceiling to max, ramping up to it, and holding the button down. Or they can change the thermal config values to make it run hotter, which will extend the turbo time.